CN113561449A - MMA continuous prepolymerization system and process thereof - Google Patents
MMA continuous prepolymerization system and process thereof Download PDFInfo
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- CN113561449A CN113561449A CN202110820965.5A CN202110820965A CN113561449A CN 113561449 A CN113561449 A CN 113561449A CN 202110820965 A CN202110820965 A CN 202110820965A CN 113561449 A CN113561449 A CN 113561449A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/92—Measuring, controlling or regulating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
- B29C48/40—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders
- B29C48/404—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders the screws having non-intermeshing parts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
- B29C48/40—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders
- B29C48/405—Intermeshing co-rotating screws
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
- C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F120/10—Esters
- C08F120/12—Esters of monohydric alcohols or phenols
- C08F120/14—Methyl esters, e.g. methyl (meth)acrylate
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Abstract
The invention relates to an MMA continuous prepolymerization system and a process thereof, which comprises an MMA tank, an initiator tank, a chain transfer agent tank, a metering pump and a reaction kettle, wherein a jacket is arranged outside the reaction kettle; a stirring paddle is arranged in the reaction kettle, and the upper end of the stirring paddle extends out of the reaction kettle and is connected with a speed reducing motor through a torque sensor; and the bottom of the reaction kettle is sent out of the extruder set by a discharge metering pump for continuous polymerization and extrusion. The method has simple process, can be suitable for supplying the pre-polymerized liquid by continuous extrusion molding, stably controls the polymerization rate and viscosity of the pre-polymerized liquid, is convenient for the time length and temperature control of the post-polymerization and extrusion, and considers both the polymerization efficiency and the extrusion efficiency.
Description
Technical Field
The invention relates to an acrylic production technology, in particular to an MMA continuous prepolymerization system and a process thereof.
Background
With the wide application of the acrylic, higher and higher requirements are provided for the production aging and quality of the acrylic. Compared with the traditional casting production, the latest extrusion molding mode is focused by related manufacturers in China, the existing MMA polymerization reaction extrusion is completed by one screw extruder, a series of processes such as feeding, mixing, polymerization reaction, devolatilization, extrusion and the like need to be completed, the polymerization reaction of MMA needs corresponding reaction residence time of 15min-20min, and if 1 screw extruder is adopted, the following problems are faced: because enough reaction time is reserved, the length of a screw polymerization reaction zone is longer, the integral length of equipment is lengthened, and the manufacturing cost is multiplied; the reaction residence time in one extruder is long, so that the final extrusion rate is limited, continuous polymerization extrusion molding cannot be realized, the productivity is indirectly reduced, and local quality difference on the same molded plate is easily caused to influence the product quality; the temperature requirements of the polymerization reaction zone and the extrusion zone are inconsistent, and the large temperature difference causes large temperature control energy loss and is not beneficial to controlling the reaction and extrusion time.
Disclosure of Invention
The invention provides an MMA continuous prepolymerization system and a process thereof, wherein the system can be suitable for supplying a prepolymerization liquid for continuous extrusion molding, stably control the polymerization rate and viscosity of the prepolymerization liquid, is convenient for controlling the time length and temperature of subsequent polymerization and extrusion and gives consideration to both the polymerization efficiency and the extrusion efficiency.
The technical scheme adopted by the invention is as follows: the utility model provides a MMA is system of prepolymerizing in succession, includes MMA groove, initiator groove, chain transfer agent groove, measuring pump and reation kettle, and the reation kettle peripheral hardware presss from both sides the cover, its characterized in that: the MMA tank, the initiator tank and the chain transfer agent tank are respectively connected to an input header pipe through a feeding metering pump, and the input header pipe is sequentially connected to the upper end of the reaction kettle through a static mixer and a one-way valve; a stirring paddle is arranged in the reaction kettle, and the upper end of the stirring paddle extends out of the reaction kettle and is connected with a speed reducing motor through a torque sensor; and the bottom of the reaction kettle is sent out of the extruder set by a discharge metering pump for continuous polymerization and extrusion.
Further, the jacket is connected with an oil mold temperature controller, and the temperature of the oil mold temperature controller is controlled to be 90-110 ℃.
Further, the reaction kettle is equipped with a radar level gauge.
An MMA continuous prepolymerization process is characterized in that:
a. material preparation and feeding: respectively adding MMA monomers, initiators and chain transfer agents in a weight ratio of 99:0.65:0.35 into each tank, injecting each tank into a reaction kettle through a metering pump according to the respective feed flow rate in a ratio, wherein the extrusion injection flow rate of the reaction kettle is 3-5kg/min, and the total amount is 80 kg;
b. heating and stirring the reaction kettle: setting the temperature of the oil temperature machine to a value between 90 and 110 ℃, heating the mixed fluid in the reaction kettle at a constant temperature, and starting a stirring paddle of the reaction kettle during heating at a rotating speed of between 50 and 80 r/min;
c. calibrating the torque: feeding for the first time, counting the discharge flow at the bottom of the reaction kettle for multiple times, sending out the polymerization liquid, detecting the different viscosity of the polymerization liquid, calibrating with a torque sensor, and sending out the polymerization liquid with the viscosity value of 1000cP to 3000cP from the reaction kettle;
d. and (3) controlling the feeding of continuous production: firstly, when the current viscosity value is > (the required viscosity value is plus 500 cp), the adding amount of an MMA monomer is increased by 6-10 percent to obtain a basic flow, and the inlet and outlet flow of a reaction kettle = the basic flow plus the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; when the current viscosity value is smaller than (the required viscosity value is-500 cp), the addition amount of the initiator is increased by 8-10% to obtain a basic flow, and the inlet and outlet flow of the reaction kettle = the basic flow-the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; thirdly, the current viscosity value is within (the required viscosity value is +/-500 cp), and the inlet flow and the outlet flow of the reaction kettle are constant;
e. the continuous polymerization is carried out according to the steps, the polymerization rate of the obtained polymerization liquid reaches 30-38%, and the polymerization liquid can be sent to an extruder set for normal reaction extrusion.
Further, the extrusion unit comprises a full-meshing homodromous rotating double-screw machine and a non-meshing heterodromous rotating double-screw machine, a discharge metering pump is connected with the feeding of the full-meshing homodromous rotating double-screw machine, the discharging of the full-meshing homodromous rotating double-screw machine is connected with the non-meshing heterodromous rotating double-screw machine, and an external extrusion die of the non-meshing heterodromous rotating double-screw machine, a plurality of devolatilization ports are arranged on the non-meshing heterodromous rotating double-screw machine, the internal temperature of the full-meshing homodromous rotating double-screw machine is 110-.
Furthermore, the two screws of the full-meshing co-rotating double screw machine are sequentially composed of a forward large-lead conveying block, a forward threaded element, a reverse kneading block, a forward kneading block, a reverse threaded element, a toothed disc, a reverse large-lead conveying block, a discharging forward threaded element and a discharging reverse threaded element from one end to the other end.
Further, the discharging position of the full-meshing co-rotating double-screw machine is arranged between the discharging forward threaded element and the discharging reverse threaded element and corresponds to the outer wall of the barrel at the tail end of the extruder.
Further, the extrusion port of the non-meshed counter-rotating double-screw machine is arranged on the outer wall of the barrel at the tail end of the extruder.
Furthermore, an extrusion port of the non-meshed counter-rotating double-screw machine is provided with a pressure sensor, the extrusion port is externally connected with a melt pump, and the melt pump is connected with an extrusion die.
Further, the internal temperature control between the forward thread element and the reverse kneading block is 110-.
According to the invention, MMA continuous prepolymerization is added in an extruder to extrude and form acrylic preorder, the viscosity in a reaction kettle is calibrated through a torque sensor and monitored in real time, the feeding amount of prepolymerization raw materials is controlled, the prepolymerization rate is effectively controlled and continuously supplied to two extruders of a subsequent extruder set to respectively complete polymerization and extrusion operations, the extruder polymerization is carried out after prepolymerization through a prepolymerization system, and the polymerization rate can finally reach the polymerization rate
Drawings
FIG. 1 is a diagram of a continuous prepolymerization system for MMA according to the present invention;
FIG. 2 is a schematic structural diagram of an external extruder set according to the present invention;
FIG. 3 is a schematic view of the fully-intermeshing co-rotating twin screw machine of FIG. 2;
FIG. 4 is a schematic view of the non-intermeshing counter-rotating twin screw machine of FIG. 2.
In the figure: an MMA tank 1, a first metering pump 2, an initiator tank 3, a second metering pump 4, a chain transfer agent tank 5, a third metering pump 6, a static mixer 7, a one-way valve 8, a reaction kettle 9, a stirring paddle 10, a torque sensor 11, a speed reducing motor 12, a discharging metering pump 13, a jacket 14, an oil mold temperature controller 15, a radar level gauge 16, a full-meshed co-rotating twin-screw machine 17, a forward large lead conveying block 18, a forward threaded element 19, a reverse kneading block 20, a forward kneading block 21, a reverse threaded element 22, a toothed disc 23, a reverse large lead conveying block 24, a discharging forward threaded element 25, a discharging reverse threaded element 26, a non-meshed counter rotating twin-screw machine 27, a discharging forward threaded element 28, a discharging reverse threaded element 29, an extrusion port 30, a pressure sensor 31, a melt pump 32 and an extrusion mold 33.
Detailed Description
The following is further described with reference to the accompanying drawings.
FIGS. 1-4 show: an MMA continuous prepolymerization system comprises an MMA tank 1, a first metering pump 2, an initiator tank 3, a second metering pump 4, a chain transfer agent tank 5, a third metering pump 6, a static mixer 7, a one-way valve 8, a reaction kettle 9, a stirring paddle 10, a torque sensor 11, a speed reducing motor 12, a discharging metering pump 13, a jacket 14, an oil mold temperature controller 15 and a radar liquid level meter 16. An MMA (methyl methacrylate) tank 1 is jointly connected with a reaction kettle 9 through a first metering pump 2, an initiator tank 3 through a second metering pump 4 and a chain transfer agent tank 5 through a third metering pump 6, then the materials are fed into the reaction kettle 9 through a static mixer 7 and a one-way valve 8, a jacket 14 is arranged outside the reaction kettle, the jacket is connected with an oil mold temperature controller 15, the temperature of the oil mold temperature controller is controlled to be 90-110 ℃, the reaction kettle is provided with a radar liquid level meter 16, a stirring paddle 10 is arranged in the reaction kettle, the upper end of the stirring paddle 10 extends out of the reaction kettle and is connected with a speed reducing motor 12 through a torque sensor 11, and the bottom of the reaction kettle 9 is sent out of an extruder set through a discharge metering pump 13 for continuous polymerization and extrusion; the extruder unit comprises a full-meshed co-rotating double screw extruder 17 and a non-meshed counter-rotating double screw extruder 27, a discharging metering pump is connected with the feeding of the full-meshed co-rotating double screw extruder, two screws of the full-meshed co-rotating double screw extruder are sequentially composed of a forward large lead conveying block 18, a forward threaded element 19, a reverse kneading block 20, a forward kneading block 21, a reverse threaded element 22, a toothed disc 23, a reverse large lead conveying block 24, a discharging forward threaded element 25 and a discharging reverse threaded element 26 from one end to the other end, the internal temperature between the forward threaded element and the reverse kneading block is controlled by 110-, the discharging of the full-meshed co-rotating twin-screw machine is connected with the non-meshed counter-rotating twin-screw machine, an extrusion port 30 of the non-meshed counter-rotating twin-screw machine is arranged on the outer wall of a barrel body at the tail end of the extruder and corresponds to the positions of a discharging forward threaded element 28 and a discharging reverse threaded element 29 on a screw of the extruder, the extrusion port 30 is provided with a pressure sensor 31, the extrusion port is externally connected with a melt pump 32, the melt pump is connected with an extrusion die 33, the non-meshed counter-rotating twin-screw machine is provided with a plurality of devolatilization ports, and the internal temperature of the non-meshed counter-rotating twin-screw machine is controlled to 160-.
The continuous prepolymerization process of the system comprises the following steps:
a. material preparation and feeding: respectively adding MMA monomers, initiators and chain transfer agents in a weight ratio of 99:0.65:0.35 into each tank, injecting each tank into a reaction kettle through a metering pump according to the respective feed flow rate in a ratio, wherein the extrusion injection flow rate of the reaction kettle is 3-5kg/min, and the total amount is 80 kg;
b. heating and stirring the reaction kettle: setting the temperature of the oil temperature machine to a value between 90 and 110 ℃, heating the mixed fluid in the reaction kettle at a constant temperature, and starting a stirring paddle of the reaction kettle during heating at a rotating speed of between 50 and 80 r/min;
c. calibrating the torque: feeding for the first time, counting the discharge flow at the bottom of the reaction kettle for multiple times, sending out the polymerization liquid, detecting the different viscosity of the polymerization liquid, calibrating with a torque sensor, and sending out the polymerization liquid with the viscosity value of 1000cP to 3000cP from the reaction kettle;
d. and (3) controlling the feeding of continuous production: firstly, when the current viscosity value is > (the required viscosity value is plus 500 cp), the adding amount of an MMA monomer is increased by 6-10 percent to obtain a basic flow, and the inlet and outlet flow of a reaction kettle = the basic flow plus the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; when the current viscosity value is smaller than (the required viscosity value is-500 cp), the addition amount of the initiator is increased by 8-10% to obtain a basic flow, and the inlet and outlet flow of the reaction kettle = the basic flow-the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; thirdly, the current viscosity value is within (the required viscosity value is +/-500 cp), and the inlet flow and the outlet flow of the reaction kettle are constant;
e. the polymerization rate of the obtained polymerization liquid reaches 30-38 percent, the polymerization liquid can be sent to an extruder unit to be extruded by a full-meshed co-rotating double screw machine and a non-meshed counter-rotating double screw machine in sequence, the polymerization rate in the full-meshed co-rotating double screw machine can reach 70-80 percent, and the polymerization rate in the non-meshed counter-rotating double screw machine can reach 90-92 percent.
Example one
The continuous MMA prepolymerization process comprises the following steps:
a. material preparation and feeding: respectively adding MMA monomers, initiators and chain transfer agents in a weight ratio of 99:0.65:0.35 into each tank, injecting each tank into a reaction kettle through a metering pump according to the respective feed flow rate in a ratio, wherein the extrusion injection flow rate of the reaction kettle is 3kg/min, and the total amount is 80 kg;
b. heating and stirring the reaction kettle: setting the temperature of the oil temperature machine to a value between 110 ℃, heating the mixed fluid in the reaction kettle at constant temperature, and starting a stirring paddle of the reaction kettle during heating at the rotating speed of 80 r/min;
c. calibrating the torque: feeding for the first time, counting the discharge flow at the bottom of the reaction kettle for multiple times, sending out the polymerization liquid, detecting the different viscosity of the polymerization liquid, calibrating with a torque sensor, and sending out the polymerization liquid with the viscosity value of 1000cP to 3000cP from the reaction kettle;
d. and (3) controlling the feeding of continuous production: if the current viscosity value is determined to be > (the required viscosity value +500 cp), the adding amount of the MMA monomer is increased by 6-10% to obtain a basic flow, and the adding amount of the MMA monomer is increased by 1% when the adding amount exceeds 50 cp on the basis of 500cp, wherein the inlet and outlet flow of the reaction kettle = the basic flow and the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; when the current viscosity value is smaller than (the required viscosity value is-500 cp), the addition amount of the initiator is increased by 8-10% to obtain a basic flow, the addition amount is increased by 1% when the addition amount is reduced by 50 cp on the basis of 500cp, and the inlet and outlet flow of the reaction kettle = the basic flow-the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; thirdly, the current viscosity value is within (the required viscosity value is +/-500 cp), and the inlet flow and the outlet flow of the reaction kettle are constant;
e. the polymerization rate of the obtained polymerization liquid reaches 38 percent, the polymerization liquid can be sent to an extruder unit to be extruded by a full-meshed co-rotating double screw machine and a non-meshed counter-rotating double screw machine in sequence, the polymerization rate in the full-meshed co-rotating double screw machine can reach 80 percent, and the polymerization rate in the non-meshed counter-rotating double screw machine can reach 92 percent.
Example two
The continuous MMA prepolymerization process comprises the following steps:
a. material preparation and feeding: respectively adding MMA monomers, initiators and chain transfer agents in a weight ratio of 99:0.65:0.35 into each tank, injecting each tank into a reaction kettle through a metering pump according to the respective feed flow rate in a ratio, wherein the extrusion injection flow rate of the reaction kettle is 4kg/min, and the total amount is 80 kg;
b. heating and stirring the reaction kettle: setting the temperature of the oil temperature machine to a value between 100 ℃, heating the mixed fluid in the reaction kettle at constant temperature, and starting a stirring paddle of the reaction kettle during heating at a rotating speed of 70 r/min;
c. calibrating the torque: feeding for the first time, counting the discharge flow at the bottom of the reaction kettle for multiple times, sending out the polymerization liquid, detecting the different viscosity of the polymerization liquid, calibrating with a torque sensor, and sending out the polymerization liquid with the viscosity value of 1000cP to 3000cP from the reaction kettle;
d. and (3) controlling the feeding of continuous production: if the current viscosity value is determined to be > (the required viscosity value +500 cp), the adding amount of the MMA monomer is increased by 6-10% to obtain a basic flow, and the adding amount of the MMA monomer is increased by 1% when the adding amount exceeds 50 cp on the basis of 500cp, wherein the inlet and outlet flow of the reaction kettle = the basic flow and the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; when the current viscosity value is smaller than (the required viscosity value is-500 cp), the addition amount of the initiator is increased by 8-10% to obtain a basic flow, the addition amount is increased by 1% when the addition amount is reduced by 50 cp on the basis of 500cp, and the inlet and outlet flow of the reaction kettle = the basic flow-the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; thirdly, the current viscosity value is within (the required viscosity value is +/-500 cp), and the inlet flow and the outlet flow of the reaction kettle are constant;
e. the polymerization rate of the obtained polymerization liquid reaches 35 percent, the polymerization liquid can be sent to an extruder unit to be extruded by a full-meshed co-rotating double screw machine and a non-meshed counter-rotating double screw machine in sequence, the polymerization rate in the full-meshed co-rotating double screw machine can reach 76 percent, and the polymerization rate in the non-meshed counter-rotating double screw machine can reach 91.5 percent.
EXAMPLE III
The continuous MMA prepolymerization process comprises the following steps:
a. material preparation and feeding: respectively adding MMA monomers, initiators and chain transfer agents in a weight ratio of 99:0.65:0.35 into each tank, injecting each tank into a reaction kettle through a metering pump according to the respective feed flow rate in a ratio, wherein the extrusion injection flow rate of the reaction kettle is 5kg/min, and the total amount is 80 kg;
b. heating and stirring the reaction kettle: setting the temperature of the oil temperature machine to a value between 90 ℃, heating the mixed fluid in the reaction kettle at a constant temperature, and starting a stirring paddle of the reaction kettle during heating at a rotating speed of 50 r/min;
c. calibrating the torque: feeding for the first time, counting the discharge flow at the bottom of the reaction kettle for multiple times, sending out the polymerization liquid, detecting the different viscosity of the polymerization liquid, calibrating with a torque sensor, and sending out the polymerization liquid with the viscosity value of 1000cP to 3000cP from the reaction kettle;
d. and (3) controlling the feeding of continuous production: if the current viscosity value is determined to be > (the required viscosity value +500 cp), the adding amount of the MMA monomer is increased by 6-10% to obtain a basic flow, and the adding amount of the MMA monomer is increased by 1% when the adding amount exceeds 50 cp on the basis of 500cp, wherein the inlet and outlet flow of the reaction kettle = the basic flow and the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; when the current viscosity value is smaller than (the required viscosity value is-500 cp), the addition amount of the initiator is increased by 8-10% to obtain a basic flow, the addition amount is increased by 1% when the addition amount is reduced by 50 cp on the basis of 500cp, and the inlet and outlet flow of the reaction kettle = the basic flow-the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; thirdly, the current viscosity value is within (the required viscosity value is +/-500 cp), and the inlet flow and the outlet flow of the reaction kettle are constant;
e. the polymerization rate of the obtained polymerization liquid reaches 30 percent, the polymerization liquid can be sent to an extruder unit to be extruded by a full-meshed co-rotating double screw machine and a non-meshed counter-rotating double screw machine in sequence, the polymerization rate in the full-meshed co-rotating double screw machine can reach 70 percent, and the polymerization rate in the non-meshed counter-rotating double screw machine can reach 90 percent.
Comparative example 1
The continuous MMA prepolymerization process comprises the following steps:
a. material preparation and feeding: respectively adding MMA monomers, initiators and chain transfer agents in a weight ratio of 99:0.65:0.35 into each tank, injecting each tank into a reaction kettle through a metering pump according to the respective feed flow rate in a ratio, wherein the extrusion injection flow rate of the reaction kettle is 3kg/min, and the total amount is 80 kg;
b. heating and stirring the reaction kettle: setting the temperature of the oil temperature machine to a value between 110 ℃, heating the mixed fluid in the reaction kettle at constant temperature, and starting a stirring paddle of the reaction kettle during heating at the rotating speed of 80 r/min;
c. the polymerization rate of the obtained polymerization liquid reaches 18 percent, the polymerization liquid can be sent to an extruder set to be extruded by a full-meshing co-rotating double screw machine and a non-meshing counter-rotating double screw machine in sequence, the polymerization rate of the extruded feed liquid in the full-meshing co-rotating double screw machine in the continuous operation without machine halt can reach 60 percent, and the polymerization rate of the extruded feed liquid in the non-meshing counter-rotating double screw machine in the continuous operation without machine halt can reach 78 percent.
Comparative example No. two
The continuous MMA prepolymerization process comprises the following steps:
a. material preparation and feeding: respectively adding MMA monomers, initiators and chain transfer agents in a weight ratio of 99:0.65:0.35 into each tank, injecting each tank into a reaction kettle through a metering pump according to the respective feed flow rate in a ratio, wherein the extrusion injection flow rate of the reaction kettle is 3kg/min, and the total amount is 80 kg;
b. heating and stirring the reaction kettle: setting the temperature of the oil temperature machine to a value between 110 ℃, heating the mixed fluid in the reaction kettle at constant temperature, and starting a stirring paddle of the reaction kettle during heating at the rotating speed of 80 r/min;
c. the continuous polymerization is carried out according to the steps, the polymerization rate of the obtained polymerization liquid can reach 18 percent through continuous discharging, the polymerization liquid can be sent to an extruder set to be extruded through a full-meshing co-rotating double screw extruder, and the polymerization rate of the extruded feed liquid can reach 60 percent through continuous operation without machine halt.
It is obvious from the above examples and comparative examples that the viscosity in the reaction kettle is effectively controlled during prepolymerization, the prepolymerization efficiency can be significantly improved, and the polymerization rate is improved by more than 50% by adopting a two-stage screw extruder to extrude in a subsequent extruder, and the final extrusion feed liquid polymerization rate can reach the level of casting molding.
Claims (10)
1. The utility model provides a MMA is system of prepolymerizing in succession, includes MMA groove, initiator groove, chain transfer agent groove, measuring pump and reation kettle, and the reation kettle peripheral hardware presss from both sides the cover, its characterized in that: the MMA tank, the initiator tank and the chain transfer agent tank are respectively connected to an input header pipe through a feeding metering pump, and the input header pipe is sequentially connected to the upper end of the reaction kettle through a static mixer and a one-way valve; a stirring paddle is arranged in the reaction kettle, and the upper end of the stirring paddle extends out of the reaction kettle and is connected with a speed reducing motor through a torque sensor; and the bottom of the reaction kettle is sent out of the extruder set by a discharge metering pump for continuous polymerization and extrusion.
2. A continuous prepolymerization system for MMA according to claim 1, wherein: the jacket is connected with an oil mold temperature controller, and the temperature of the oil mold temperature controller is controlled to be 90-110 ℃.
3. A continuous prepolymerization system for MMA according to claim 1, wherein: the reaction kettle is provided with a radar liquid level meter.
4. An MMA continuous prepolymerization process is characterized in that:
a. material preparation and feeding: respectively adding MMA monomers, initiators and chain transfer agents in a weight ratio of 99:0.65:0.35 into each tank, injecting each tank into a reaction kettle through a metering pump according to the respective feed flow rate in a ratio, wherein the extrusion injection flow rate of the reaction kettle is 3-5kg/min, and the total amount is 80 kg;
b. heating and stirring the reaction kettle: setting the temperature of the oil temperature machine to a value between 90 and 110 ℃, heating the mixed fluid in the reaction kettle at a constant temperature, and starting a stirring paddle of the reaction kettle during heating at a rotating speed of between 50 and 80 r/min;
c. calibrating the torque: feeding for the first time, counting the discharge flow at the bottom of the reaction kettle for multiple times, sending out the polymerization liquid, detecting the different viscosity of the polymerization liquid, calibrating with a torque sensor, and sending out the polymerization liquid with the viscosity value of 1000cP to 3000cP from the reaction kettle;
d. and (3) controlling the feeding of continuous production: firstly, when the current viscosity value is > (the required viscosity value is plus 500 cp), the adding amount of an MMA monomer is increased by 6-10 percent to obtain a basic flow, and the inlet and outlet flow of a reaction kettle = the basic flow plus the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; when the current viscosity value is smaller than (the required viscosity value is-500 cp), the addition amount of the initiator is increased by 8-10% to obtain a basic flow, and the inlet and outlet flow of the reaction kettle = the basic flow-the total weight (80 kg) in the kettle x (1-required viscosity value/current viscosity value) x 0.2; thirdly, the current viscosity value is within (the required viscosity value is +/-500 cp), and the inlet flow and the outlet flow of the reaction kettle are constant;
e. the continuous polymerization is carried out according to the steps, the polymerization rate of the obtained polymerization liquid reaches 30-38%, and the polymerization liquid can be sent to an extruder set for normal reaction extrusion.
5. A continuous prepolymerization process for MMA according to claim 1 or 4, characterized by: the extrusion unit comprises a full-meshing homodromous rotating double-screw machine and a non-meshing heterodromous rotating double-screw machine, a discharge metering pump is connected with the feeding of the full-meshing homodromous rotating double-screw machine, the discharge of the full-meshing homodromous rotating double-screw machine is connected with the non-meshing heterodromous rotating double-screw machine, and an extrusion die is externally connected with the non-meshing heterodromous rotating double-screw machine, a plurality of devolatilization ports are arranged on the non-meshing heterodromous rotating double-screw machine, the internal temperature of the full-meshing homodromous rotating double-screw machine is 110-.
6. A continuous prepolymerization process for MMA according to claim 5, characterized by: two screws of the full-meshing co-rotating double screw machine are composed of a forward large-lead conveying block, a forward threaded element, a reverse kneading block, a forward kneading block, a reverse threaded element, a tooth-shaped disc, a reverse large-lead conveying block, a discharging forward threaded element and a discharging reverse threaded element from one end to the other end in sequence.
7. A continuous prepolymerization process for MMA according to claim 6, characterized by: the discharging position of the full-meshing co-rotating double-screw machine is arranged between the discharging forward threaded element and the discharging reverse threaded element and corresponds to the outer wall of the barrel at the tail end of the extruder.
8. A continuous prepolymerization process for MMA according to claim 5, characterized by: the extrusion port of the non-meshed counter-rotating double-screw machine is arranged on the outer wall of the barrel at the tail end of the extruder.
9. A continuous prepolymerization process for MMA according to claim 8, characterized by: and an extrusion port of the non-meshed counter-rotating double-screw machine is provided with a pressure sensor, the extrusion port is externally connected with a melt pump, and the melt pump is connected with an extrusion die.
10. A continuous prepolymerization process for MMA according to claim 6, characterized by: the internal temperature control between the forward thread element and the reverse kneading block is 110-.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110820965.5A CN113561449A (en) | 2021-07-20 | 2021-07-20 | MMA continuous prepolymerization system and process thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110820965.5A CN113561449A (en) | 2021-07-20 | 2021-07-20 | MMA continuous prepolymerization system and process thereof |
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| Publication Number | Publication Date |
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| CN113561449A true CN113561449A (en) | 2021-10-29 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202110820965.5A Withdrawn CN113561449A (en) | 2021-07-20 | 2021-07-20 | MMA continuous prepolymerization system and process thereof |
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| Country | Link |
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Application publication date: 20211029 |